Compositions and methods for reducing microbial contamination in meat processing

ABSTRACT

The present invention is directed to compositions, methods, and systems for reducing microbial contamination in meat processing. In accordance with one aspect of the invention, disinfection composition and/or recycled disinfection composition comprising an acid, a buffer, and optionally an antimicrobial metal is applying to a carcass during at least one processing step of sacrificing, scalding, feather/hair/hide removal, eviscerating, and washing. Other aspects of the invention provide a carcass processing system comprising processing stations intermittently fluidly connected via a buffered acidic disinfection composition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.11/674,588, filed on Feb. 13, 2007, which in turn claims priority toU.S. Provisional Application Ser. No. 60/547,991, filed Feb. 26, 2004;each of which are incorporated herein by reference in their entirety.This application also claims priority from U.S. Provisional ApplicationSer. No. 60/801494, filed on May 17, 2006, incorporated herein byreference in its entirety.

FIELD OF THE INVENTION

The present invention generally relates to reduction of pathogen load inmeat processing.

BACKGROUND OF THE INVENTION

Pathogen contamination of poultry carcasses is a major concern ofchicken processors in the U.S. and the rest of the world. U.S.processors particularly face recent stringent governmental requirementsrelated to maximal pathogen levels for meat and poultry slaughterfacilities (see e.g., United States Department of Agriculture, FederalRegister, 1996. 9 CFR Part 304 et al., Pathogen Reduction; HazardAnalysis and Critical Control Point (HACCP) Systems; Final Rule. Vol.61, Number 144, pp. 38846-38848). New interventions will be required forprocessors to meet the new requirements.

Poultry is processed primarily to convert the bird's muscles into meat,to remove the unwanted components of the bird (blood, feathers, viscera,feet, and head), and to keep microbiological contamination at a minimum.The ultimate quality of the final product depends not only on thecondition of the birds when they arrive at the plant, but also on howthe bird is handled during processing. Various approaches have beenutilized to lower pathogen prevalence on carcasses. The three maintargeted areas for pathogen reduction include scald-tanks, rinsesystems, and immersion chillers. For example, processors have increasedwater usage in rinses, scalders, and chillers from approximately 4-5gallons per carcass to 7-10 gallons per carcass. Other processors haveused a water recycling system that takes all rinse water from equipmentsprays and carcass rinsers in the plant, and cleans the water usingdiatomaceous earth filters. The water is then ozonated, heated, andreturned to the scalder.

Some processors have attempted to add sanitizers to rinse waters orcommon baths such as the scalder or chiller (see e.g., Okrend et al.(1986) J. Food Protect. 49, 500-503). The scalder is a common bathcontaining hot water in which the birds are submerged to soften featherfollicles to aid in feather removal. The scalder is an area in whichcross-contamination with Salmonella and other pathogenic bacteria isknown to occur. But use of a sanitizer in the scalder to decreasecross-contamination has been difficult. Such a sanitizer must beresistant to binding with organic material, must not be driven off byhigh temperatures, and must have a relatively quick kill time. Thosesanitizers currently known and used in the industry do not meet one ormore of these requirements.

In poultry processing facilities throughout the U.S., rinse waterscontaining disinfectant are used throughout the plant. Locations whererinses are commonly used include: pre-scalding, picking, post-picking,post-evisceration, inside/outside bird washers (IOBW) prior to chilling,and automated reprocessing antimicrobial rinses prior to chilling.Additionally, most pieces of equipment with food contact surfaces arerinsed continually with water containing disinfectant.

The most commonly used disinfectant associated with equipment andcarcass rinses in the U.S. is chlorine in the form of sodiumhypochlorite (bleach). If the pH of the water is too high (>8.0), thenbleach added to chlorinated rinse waters or chiller water will beineffective, as the bleach will drive the pH up even further. At pH'sabove 8.0, chlorine is not found in its active form (hypochlorous acid)in high quantities and is ineffective for killing bacteria. Furthermore,if lye is used in the water reservoir that supplies the plant as a meansof reducing the effects of acid rain, and the pipe that feeds the plantpicks up this lye, then the pH of the water may be driven up to 10 orgreater, causing problems with the chlorine as previously discussed. Ifammonia has been added to the incoming water, there is a greaterlikelihood that when chlorine is added to the water, trichloramines willbe formed, resulting in noxious odors.

Disinfectants approved for automated reprocessing of carcassescontaminated by fecal material include: trisodium phosphate (TSP),acidulated sodium chlorite (e.g., Sanova), peroxyacetic acid (e.g.,Inspexx), and chlorine dioxide. But none of these disinfectants havebeen shown to be suitable for scalder use.

TSP is costly to use because of the high concentration (10%) used oncarcasses. Residual TSP on carcasses causes the chiller water pH toincrease dramatically. In plants where TSP is used, the chiller waterwill generally be in the pH range of 9.7 to 10.5. This is extremely highand prevents chlorine from being converted to its effective form. Often,use of TSP systems result in the increase of Salmonella prevalence whencompared to levels prior to using TSP. To counter the effects ofTSP-mediated pH increases, CO₂ gas systems have been added to theaeration systems of chillers as a means of reducing the pH so as tomaintain the effectiveness of chlorine. It has also been reported thatListeria monocytogenes is resistant to the effects of trisodiumphosphate (TSP). Furthermore, exposure to a high (8%) level of TSP for10 minutes at room temperature is required to reduce bacterial numbersby 1 log 10 after a colony has grown on a surface and a protective layer(biofilm) has been formed.

Acidulated sodium chlorite (Sanova) is an approved poultry spray or dipat 500 to 1200 ppm singly or in combination with other generallyregarded as safe (GRAS) acids to achieve a pH of 2.3 to 2.9 in automatedreprocessing methods. In chiller water, sodium chlorite is limited to 50to 150 ppm singly or in combination with other GRAS acids to achieve apH of 2.8 to 3.2. Studies have shown that it can reduce Salmonellacontamination from 31.6% prevalence to 10% prevalence (see e.g., Kemp etal. (2001) J. Food Protect. 64, 807-812). Many poultry processingfacilities have switched from TSP systems to Sanova as an approvedautomated reprocessing system because it appears to reduce Salmonellamore effectively than TSP.

Peroxyacetic acid (Inspexx), composed of hydrogen peroxide and aceticacid, has only recently been approved for use in the U.S. as anautomated reprocessing disinfectant. Very little published research dataexists regarding its efficacy in processing environments.

Some processors have attempted to reduce the temperature of one or morescald-tanks in an effort to increase yield (decreases the amount of fatcooked off of the carcass). For example, some processors have loweredthe temperature of the first scald-tank to 108° F. (42.2° C.). Whileyield increases have been reported, pathogen count also greatlyincreases. At 108° F. (42.2° C.), most pathogens grow quite readily andthey have all of the requirements for growth available (propertemperature, nutrients, pH, moisture, etc.). Thus, it is a generalpractice in the art that the temperature of the scalder should bemaintained as high as possible without causing visible defects tofinished carcasses, such as breast striping. Various scientific reportsrecommend no less than 10° F. higher than the maximum growth temperatureof the pathogen. For example, Salmonella has a maximum growthtemperature of 113° F. (45° C.). Thus, according to the conventionalpractice, the scalder should be no less than 123° F. (50.6° C.) in orderto ensure that the pathogen cannot proliferate.

Processors have focused attention on bacterial reduction at theimmersion chiller stage of processing (see e.g., Izat et al. (1989) J.Food Protect. 52, 670-673). Organic material in the chiller is primarilydetermined by the flow rate, flow direction, and the cleanliness of thescalder. The pH, temperature, flow rate, flow direction, chlorineconcentration, and concentration of organic material (digesta, fat,blood) are all factors the pathogen-chiller load. The chlorine demand ofan average chiller is very high at around 400 ppm because of the highcontent of organic material in the water. Because the maximum limit forchlorine use in the U.S. is only 50 ppm, there is rarely any truechlorine residual in the chiller overflow. Generally, the chiller pH is6.5 to 7.5, the temperature below 40° F. (4.4° C.), the flow rateapproximately ¾ to 1 gallon per bird), and the flow directioncounter-current. The recycled chiller water can be ozonated and filteredto decrease organic material and to add an additional level ofsanitation.

Thus there exists a need for methods to reduce pathogen load in meatprocessing plants, especially with regard to disinfectants compatiblewith high temperature, high organic load environments.

SUMMARY OF THE INVENTION

The present invention is generally directed to methods to reducepathogen contamination during food processing. The methods include theuse of particular disinfection agents suited for processing of foodproducts, preferably meat processing, and more preferably poultryprocessing, at or during one or more processing steps. Thesedisinfection agents are generally non-oxidizing, acidic, buffereddisinfectants that function efficiently in high temperature, highorganic load, aqueous environments.

One aspect of the invention is directed to methods for reducing amicrobial population on an animal carcass during processing includingthe steps of: (a) sacrificing an animal to form an animal carcass, (b)scalding an animal carcass, (c) removing feathers, hair, or hide fromthe scalded carcass, (d) eviscerating the defeathered, dehaired, ordehided carcass, (e) washing the eviscerated carcass, (f) chilling theeviscerated carcass, and (g) applying to the carcass during processing adisinfection composition including an acid and a buffer, in an amountand time sufficient to reduce a microbial population, wherein applyingthe disinfection composition (g) is performed during or immediatelyafter at least one of steps (a), (b), (c), (d), (e), and (f). Inaccordance with a further embodiment, the methods can further includethe steps of (h) recovering at least a portion of the applieddisinfection composition, (i) adding to the recovered composition asufficient amount of disinfection composition to yield a recycleddisinfection composition, and (j) applying the recycled composition to acarcass during processing, wherein applying the recycled disinfectioncomposition (j) is performed during or immediately after at least one ofsteps (a), (b), (c), (d), (e), and (f).

In various embodiments, the methods can include applying thedisinfection composition and/or the recycled composition by submersing,rinsing, or spraying the carcass in or with the composition. In variousembodiments, the methods can include applying the disinfectioncomposition and/or the recycled composition at least by (1) submersingthe carcass during scalding or (2) rinsing, spraying, or submersing thecarcass after scalding but before eviscerating. In various embodiments,the methods above can include applying the disinfection composition orthe recycled composition at least by (1) submersing the carcass duringscalding, (2) rinsing, spraying, or submersing the carcass afterscalding and before eviscerating, or (3) submersing the carcass duringchilling.

In various embodiments, the methods can include rinsing, spraying, orsubmersing the carcass after scalding but before eviscerating isperformed at a sanitization station, wherein the sanitization station isintermittently fluidly connected to (1) an apparatus for removingfeathers, hair, or hide, (2) an apparatus for scalding, or (3) both anapparatus for removing feathers, hair, or hide and an apparatus forscalding, such that the recycled composition can be distributed from thesanitization station to the feather, hair, or hide removal apparatus,the scalder apparatus, or both the feather, hair, or hide removalapparatus and the scalder apparatus.

In various embodiments, the methods can include the application of adisinfection composition during submersion scalding, wherein thescalding occurs at a reduced temperature such that post-scalding carcassyield is increased. The scalding in at least one scalding tank can occurat a temperature from about 110° F. to less than about 123° F. In afurther embodiment, scalding the animal carcass occurs in at least threescalding tanks; a first scalding tank operated at about 110° F. to about120° F.; a second scalding tank operated at about 110° F. to about 125°F.; and a third scalding tank operated at about 120° F. to about 140° F.

In various embodiments, the disinfection composition and/or the recycledcomposition is of a pH from about 1.5 to about 4.0. In a furtherembodiment, the disinfection composition is of a pH of about 2 to about3.

In various embodiments, the disinfection composition can include (1)sulfuric acid and (2) ammonium sulfate or sodium sulfate. In furtherembodiments, the disinfection composition can also include anantimicrobial metal. Such antimicrobial metal can be selected fromcopper, zinc, magnesium, silver, or iron. In various embodiments, theantimicrobial metal is copper in an active ionic form. In furtherembodiments, the disinfection composition has a copper concentration ofabout 1 ppm to about 20 ppm or is added to carcass processing water inan amount sufficient to provide a copper concentration of about 1 ppm toabout 20 ppm. In further embodiments, the disinfection composition has acopper concentration of about 2 ppm to about 4 ppm or is added tocarcass processing water in an amount sufficient to provide a copperconcentration of about 2 ppm to about 4 ppm. In further embodiments, thedisinfection composition has a copper concentration of about 3 ppm or isadded to carcass processing water in an amount sufficient to provide acopper concentration of about 3 ppm.

In various embodiments, the disinfection composition can include (i)sulfuric acid, (ii) ammonium sulfate or sodium sulfate, and (iii) coppersulfate. In a further embodiment, the disinfection composition caninclude sulfuric acid, ammonium sulfate, and copper sulfate. In afurther embodiment, the disinfection composition includes about 98% toabout 99% water; about 0.1% to about 0.5% copper sulfate; about 0.1% toabout 0.5% sulfuric acid; about 0.1% to about 0.5% ammonium sulfate; andhas a pH of about 2 to about 3; a specific gravity at 25° C. of about1.002; a boiling point of about 212° F.; and a freezing point of about32° F.

In various embodiments, the disinfection composition can further includea stabilizing agent, wetting agent, hydrotrope, thickener, foamingagent, acidifier, pigment, dye, surfactant, or a combination thereof.

In various embodiments, the carcass is a poultry carcass, a beefcarcass, or a pork carcass. In a further embodiment, the carcass is apoultry carcass. In a further embodiment, the poultry is a chicken,turkey, ostrich, game hen, squab, guinea fowl, pheasant, duck, goose, oremu carcass.

Another aspect of the invention is directed to a carcass processingsystem including a scalding station, a feather, hair, or hide removalstation, and a sanitization station, wherein each station isintermittently fluidly connected via a buffered acidic disinfectioncomposition. In various embodiments, the carcass can be a poultry, beef,or pork carcass. In a further embodiment, the carcass is a poultrycarcass. In a further embodiment, the poultry is a chicken, turkey,ostrich, game hen, squab, guinea fowl, pheasant, duck, goose, or emucarcass. In various embodiments, the disinfection composition includessulfuric acid; ammonium sulfate or sodium sulfate; and an antimicrobialmetal. In further embodiments, the antimicrobial metal is copper in anactive ionic form and the disinfection composition has a copperconcentration of about 1 ppm to about 20 ppm or is added to carcassprocessing water in an amount sufficient to provide a copperconcentration of about 1 ppm to about 20 ppm. In various embodiments,the carcass processing system includes at least three scalding tanks,wherein a first scalding tank is operated at about 110° F. to about 120°F.; a second scalding tank is operated at about 110° F. to about 125°F.; and a third scalding tank is operated at about 120° F. to about 140°F.

Other objects and features will be in part apparent and in part pointedout hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Those of skill in the art will understand that the drawings, describedbelow, are for illustrative purposes only. The drawings are not intendedto limit the scope of the present teachings in any way.

FIG. 1 is a series of process flow diagrams. FIG. 1A depicts an overviewof an animal carcass processing system. FIG. 1B depicts an alternativeof a microorganism intervention system according to the presentinvention.

FIG. 2 is a process flow diagram depicting an alternative of amicroorganism intervention system according to the present invention.

FIG. 3 is a process flow diagram for Tasker Blue® disinfectant agentapplication to poultry carcasses during processing as used in severalstudies. Further details as to methodology are provided in Example 1.

FIG. 4 is a bar graph showing the effect of the disinfectant TaskerBlue® on aerobic plate counts on broiler chicken carcasses duringscalding. The log of colony forming units is shown over 13 days forcontrol and treatment groups. An asterisk indicates a significantdifference from control at p≦0.05. Additional details regardingmethodology are presented in Example 1.

FIG. 5 is a bar graph showing the effect of the disinfectant TaskerBlue® on aerobic plate counts on broiler chicken carcasses aftertreatment in scalder and a post-pick dip solution. The log of colonyforming units is shown over 13 days for control and treatment groups. Anasterisk indicates a significant difference from control at p≦0.05.Additional details regarding methodology are presented in Example 1.

FIG. 6 is a bar graph showing the effect of the disinfectant TaskerBlue® on Escherichia coli counts on broiler chicken carcasses duringscalding. The log of colony forming units is shown over 13 days forcontrol and treatment groups. An asterisk indicates a significantdifference from control at p≦0.05. Additional details regardingmethodology are presented in Example 1.

FIG. 7 is a bar graph showing the effect of the disinfectant TaskerBlue® on Escherichia coli counts on broiler chicken carcasses aftertreatment in scalder and a post-pick dip solution. The log of colonyforming units is shown over 13 days for control and treatment groups. Anasterisk indicates a significant difference from control at p≦0.05.Additional details regarding methodology are presented in Example 1.

FIG. 8 is a bar graph showing the effect of the disinfectant TaskerBlue® on Salmonella prevalence on broiler chicken carcasses duringscalding. The percent prevalence is shown over 13 days for control andtreatment groups. A single asterisk indicates a significant differencefrom control at p≦0.05, while a double asterisk indicates a significantdifference from control at p≦0.06. Additional details regardingmethodology are presented in Example 1.

FIG. 9 is a bar graph showing the effect of the disinfectant TaskerBlue® on Salmonella prevalence on broiler chicken carcasses aftertreatment in scalder and a post-pick dip solution. The percentprevalence is shown over 13 days for control and treatment groups. Asingle asterisk indicates a significant difference from control atp≦0.05. Additional details regarding methodology are presented inExample 1.

FIG. 10 is a process flow diagram for the treatment group in studiesexamining Tasker Blue® disinfectant agent application to poultrycarcasses at different scalder tank temperatures during processing asemployed in Example 2. Further details as to methodology, includingscalder tank temperatures, are provided in Example 2.

FIG. 11 is a process flow diagram for the control group in studiesexamining Tasker Blue® disinfectant agent application to poultrycarcasses at different scalder tank temperatures during processing asemployed in Example 2. Further details as to methodology, includingscalder tank temperatures, are provided in Example 2.

FIG. 12 is a process flow diagram of poultry processing depictingcollection points in studies examining Tasker Blue® disinfectant agentapplication to poultry carcasses at different scalder tank temperaturesduring processing as employed in Example 2. Further details as tomethodology, including scalder tank temperatures, are provided inExample 2.

FIG. 13 is a bar graph showing the broiler carcass yield (post-hoccutter) at traditional scalding temperatures versus low scaldingtemperatures in combination with the disinfectant Tasker Blue®. Theaverage weight (lbs) is shown for three replicates each of control anddisinfectant treatment. Control scalder temperatures were 132°, 134°,and 136° F. for the first, second, and third scalder tanks,respectively. Scalder temperatures for the disinfectant treated tankswere 113°, 123°, and 138° F. for the first, second, and third scaldertanks, respectively. Mean values with different letters aresignificantly different at p<0.0001. Additional details regardingmethodology are presented in Example 2.

FIG. 14 is a bar graph showing the broiler carcass yield (pre-IOBW) attraditional scalding temperatures versus low scalding temperatures incombination with the disinfectant Tasker Blue®. The average weight (lbs)is shown for three replicates each of control and disinfectanttreatment. Control scalder temperatures were 132°, 134°, and 136° F. forthe first, second, and third scalder tanks, respectively. Scaldertemperatures for the disinfectant treated tanks were 110°, 114°, and134° F. for the first, second, and third scalder tanks, respectively.Mean values with different letters are significantly different atp<0.0001. Additional details regarding methodology are presented inExample 2.

FIG. 15 is a bar graph showing the effect of Tasker Blue® applied duringscalding, spraying, and chilling on Escherichia coli populations onbroiler chicken carcasses. The number of colony forming units (log₁₀units/mL) is shown over three replicates for control and disinfectanttreated carcasses. Mean values with different letters are significantlydifferent at p≦0.05). Additional details regarding methodology arepresented in Example 3.

FIG. 16 is a bar graph showing the effect of Tasker Blue® applied duringscalding, spraying, and chilling on Salmonella typhimurium prevalence onbroiler chicken carcasses. The percentage of Salmonella positive chickencarcasses is shown over three replicates for control and disinfectanttreated carcasses. Mean values with different letters are significantlydifferent at p≦0.05). Additional details regarding methodology arepresented in Example 3.

FIG. 17 is a process flow diagram depicting the impingement system forcollecting air samples over poultry scalders treated with Tasker Blue®disinfecting agent. Further methodology information is provided inExample 4.

FIG. 18 is a bar graph showing the levels of ammonium sulfate, sulfuricacid, and copper sulfate in air collected above untreated (control) andtreated scalder water containing Tasker Blue® disinfecting agent.Different letters within a particular chemical indicate a significantdifference at p<0.0001. Further methodology information is provided inExample 4.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is generally directed to methods to reducepathogen contamination during food processing. The methods include theuse of particular disinfection agents suited for processing of foodproducts, preferably meat processing, and more preferably poultryprocessing, at or during one or more processing steps.

Food Products

A food product generally includes any food substance that might requiretreatment with an antimicrobial agent or composition and that is ediblewith or without further preparation. Food products can include, forexample, meat (e.g. red meat and pork), seafood, poultry, fruits andvegetables, eggs, egg products, ready to eat food, wheat, seeds,sprouts, seasonings, or a combination thereof. Red meat generallyincludes the meat of mammals such as beef, veal, mutton, lamb, rabbit,and horse. Produce generally includes food products such as fruits andvegetables and plants or plant-derived materials that are typically solduncooked and, often, unpackaged, and that can sometimes be eaten raw.

The methods described herein can be applied to meat processing,especially poultry processing. A meat product generally includes variousforms of animal flesh, including muscle, fat, organs, skin, bones, andbody fluids and like components that form the animal. Animal fleshincludes the flesh of mammals, birds, fishes, reptiles, amphibians,snails, clams, crustaceans, other edible species such as lobster, crab,etc., or other forms of seafood. The forms of animal flesh include, forexample, the whole or part of animal flesh, alone or in combination withother ingredients. Typical forms include, for example, processed meatssuch as cured meats, sectioned and formed products, minced products,finely chopped products, ground meat and products including ground meat,whole products, and the like. For example, the methods of the presentinvention can be applied to processing of retail seafood. Suchapplication provides odor knockdown and enhanced shelf-life.

Preferably, the methods described herein are applied to poultryprocessing. Poultry generally includes various forms of any bird kept,harvested, or domesticated for meat or eggs, and including chicken,turkey, ostrich, game hen, squab, guinea fowl, pheasant, quail, duck,goose, emu, or the like and the eggs of these birds. Poultry includeswhole, sectioned, processed, cooked or raw poultry, and encompasses allforms of poultry flesh, by-products, and side products. The flesh ofpoultry includes muscle, fat, organs, skin, bones and body fluids andlike components that form the animal. Forms of animal flesh include, forexample, the whole or part of animal flesh, alone or in combination withother ingredients. Typical forms include, for example, processed poultrymeat, such as cured poultry meat, sectioned and formed products, mincedproducts, finely chopped products and whole products. Poultry processingmethodology is well known in the art. Except as otherwise noted herein,therefore, the process of the present invention can be carried out inaccordance with such processes.

Application

Food products can be contacted with the disinfection agent by any methodor apparatus suitable for applying the disinfection agent. For example,the disinfection agent can be delivered as a vented densified fluidcomposition, a spray of the agent, by immersion in the agent, by foam orgel treating with the agent, or the like, or any combination thereof.Contact with a gas, a spray, a foam, a gel, or by immersion can beaccomplished by a variety of methods known to those of skill in the artfor applying agents to food.

The disinfection agents described herein can be employed for a varietyof disinfection purposes, preferably as or for forming water-basedsystems for processing and/or washing animal carcasses. The presentcompositions and methods can be employed for processing meat at any stepfrom gathering the live animals through packaging the final product. Forexample, the present compositions and methods can be employed forwashing, rinsing, chilling, or scalding carcasses, carcass parts, ororgans for reducing contamination of these items withspoilage/decay-causing bacteria, and pathogenic bacteria.

Carcass Processing

Before processing, live animals are generally transported to andgathered at the beginning of a processing line. Animals can be washedbefore entering the processing line. Processing typically begins withsacrificing the animal, typically by electrical stunning, followed byneck cutting and bleeding. A first washing step, known as scalding (e.g.submersion or immersion scalding) typically follows bleeding and loosensattachment of feathers, hair or hide of the animal. For example, poultryscalding loosens the attachment of feathers to the poultry skin.Submersion scalding can be accomplished according to the methods andemploying compositions of the present invention. Submersion scaldingtypically includes immersing a stunned and bled animal (e.g., poultry)into a scalding hot bath of water or a liquid antimicrobial composition,typically at a temperature of about 50 to about 80° C., preferably about50 to about 60° C. The liquid disinfection composition in the bath canbe agitated, sonicated, or pumped to increase contact of the compositionwith the carcass. Scalding is generally conducted in a scald tank ortrough, which contains the scalding liquid with sufficient liquid depthto completely submerse the poultry carcass. The carcass is generallytransported through the tank or trough by conveyor at a speed thatprovides a few minutes in the scalding liquid.

According to the present invention, the scalding bath can include adisinfection composition described herein. The scalding bath can alsoinclude one or more of the additional ingredients permitted in scaldingbaths.

Inclusion of the disinfection solution in the scalding bath allowsoperation at a reduced temperature while still reducing pathogencontamination levels. Such reduction in temperature, allowed by thedisinfection composition, provides a yield increase for post-scaldercarcasses. In the absence of disinfection agent, operation of thescalder bath at lower temperature generally results in greatly increasedpathogen prevalence and also inferior feather, hair, or hide removal.For example, in poultry processing, it is general practice to maintainthe scalder a minimum of about 10° F. above the maximum growthtemperature of Salmonella (113° F.). So, without using a disinfectioncomposition, the lowest temperatures suggested in the art for thescalder bath is about 123° F. Addition of acidic buffered disinfectionagents, described herein, allows the scalder baths to be maintainedbelow this temperature while also providing reductions in pathogencontamination in the scalder water and on the emerging carcasses. Forexample, one or more poultry scalding bath can be maintained betweenabout 110° F. and 123° F. Furthermore, scalder tanks operated at or nearthe maximum growth temperature of a microorganism can be used incombination with scalder tanks operated at conventional temperatures.For example, a sequence of three scalder tanks can be operated at about110-120° F.; about 110-125° F. and about 120-140° F. respectively.Increases in yield resulting from lower scalder temperatures can include0.5%, 1.0%, 1.5%, 2%, 2.5%, 3%, 3.5%, or 4% or more. Preferably,increases in yield resulting from lower scalder temperatures are 0.5% orgreater.

After submersion scalding, the carcass is typically defeathered,dehaired, or dehided, and, optionally, singed before the next washingprocess. In the case of poultry processing, this second washing processis generally known as “dress” rinsing, “New York dress” rinsing, orpost-pick rinsing, which rinses residual feathers and follicle residuesfrom the carcass. Dress rinsing typically includes spraying a pickedcarcass with water, typically at a temperature of about 5 to about 30°C. To increase contact with the carcass, the disinfection compositionsin the spray water can be applied at higher pressures, flow rates,temperatures, or with agitation or ultrasonic energy. Dress rinsing istypically accomplished with a washing apparatus such as a wash or spraycabinet with stationary or moving spray nozzles. Alternatively, a“flood”-rinsing or liquid submersion washing apparatus can be usedimmediately after picking.

According to the present invention, post-scalding rinsing (e.g., poultrydress rinsing) can be accomplished employing a disinfection compositiondescribed herein.

Dress rinsing is typically a final washing step before dismembering thecarcass. Dismembering can include removing the head, the feet,eviscerating, and removing the neck, in any order commonly employed incarcass processing. The dismembered and eviscerated carcass can then besubjected to a washing step. In poultry processing, such washing step isknown as inside-outside bird washing (IOBW). Inside-outside bird washingwashes the interior (body cavity) and exterior of the bird.Inside-outside bird washing typically includes rinsing the interior andexterior surfaces of the carcass with streams or floods of water,typically at a temperature of about 5 to about 30° C. To increasecontact with the carcass, the disinfection compositions in the spraywater can be applied at higher pressures, flow rates, temperatures, orwith agitation or ultrasonic energy. Inside-outside bird washing isgenerally accomplished by an apparatus that floods the bird carcass withstreams of water in the inner cavity and over the exterior of thecarcass. Such an apparatus can include a series of fixed spray nozzlesto apply disinfection composition to the exterior of the bird and arinse probe or bayonet that enters and applies antimicrobial compositionto the body cavity.

According to the present invention, final washing (e.g., IOBW in poultryprocessing) can be accomplished employing a disinfection compositiondescribed herein.

After washing, both the interior and the exterior of the bird can besubjected to further decontamination. This further decontamination canbe accomplished in part by a step commonly known as antimicrobial sprayrinsing, sanitizing rinsing, or finishing rinsing. Such rinsingtypically includes spraying the interior and exterior surfaces of thecarcass with water, typically at a temperature of about 5 to about 30°C. To increase contact with the carcass, the disinfection compositionsin the spray water can be applied using fixed or articulating nozzles,at higher pressures, flow rates, temperatures, with agitation orultrasonic energy, or with rotary brushes. Spray rinsing is typicallyaccomplished by an apparatus such as a spray cabinet with stationary ormoving spray nozzles. The nozzles create a mist, vapor, or spray thatcontacts the carcass surfaces.

According to the present invention, antimicrobial spray rinsing,sanitizing rinsing, or finishing rinsing can be accomplished employing adisinfection composition described herein.

After spray rinsing, the bird can be made ready for packaging or forfurther processing by chilling, specifically submersion chilling or airchilling. Submersion chilling both washes and cools the bird to retainquality of the meat. Submersion chilling typically includes submersingthe carcass completely in water or slush, typically at a temperature ofless than about 5° C., until the temperature of the carcass approachesthat of the water or slush. Chilling of the carcass can be accomplishedby submersion in a single bath, or in two or more stages, each of alower temperature. Water can be applied with agitation or ultrasonicenergy to increase contact with the carcass. Submersion chilling istypically accomplished by an apparatus such as a tank containing thechilling liquid with sufficient liquid depth to completely submerse thepoultry carcass. The carcass can be conveyed through the chiller byvarious mechanisms, such as an auger feed or a drag bottom conveyor.Submersion chilling can also be accomplished by tumbling the carcass ina chilled water cascade.

According to the present invention, submersion chilling can beaccomplished employing a disinfection composition described herein.

Like submersion chilling, air chilling or cryogenic chilling cools thecarcass to retain quality of the meat. Air cooling can be less effectivefor decontaminating the carcass, as the air typically would notdissolve, suspend, or wash away contaminants. Air chilling with a gasincluding an disinfection agent can, however, reduce the burden ofmicrobial, and other, contaminants on the carcass. Air chillingtypically includes enclosing the carcass in a chamber having atemperature below about 5° C. until the carcass is chilled. Air chillingcan be accomplished by applying a cryogenic fluid or a gas or arefrigerated gas as a blanket or spray.

According to the present invention, air chilling can be accomplishedemploying a disinfection composition described herein. For example, airchilling compositions can include a gaseous or densified fluiddisinfection composition.

After chilling, the carcass can be subjected to additional processingsteps including weighing, quality grading, allocation, portioning,deboning, and the like. This further processing can also include methodsor compositions according to the present invention for washing withdisinfection compositions. For example, it can be advantageous to washpoultry portions, such as legs, breast quarters, wings, and the like,formed by portioning the bird. Such portioning forms or reveals newmeat, skin, or bone surfaces which may be subject to contamination andbenefit from treatment with a disinfection composition. Similarly,deboning a carcass or a portion of a carcass can expose additional areasof the meat or bone to microbial contamination. Washing the debonedcarcass or portion with a disinfection composition described herein canadvantageously reduce any such contamination. In addition, during anyfurther processing, the deboned meat can also come into contact withmicrobes, for example, on contaminated surfaces. Washing the debonedmeat with a disinfection composition can reduce such contamination.Washing can be accomplished by spraying, immersing, tumbling, or acombination thereof, or by applying a gaseous or densified fluiddisinfection composition.

Usable side products of meat processing include heart, liver, andgizzard (e.g. giblets), neck, and the like. These are typicallyharvested later in processing, and are sold as food products. Of course,microbial contamination of such food products is undesirable. Thus,these side products can also be washed with a disinfection compositionin methods of the present invention. Typically, these side products willbe washed after harvesting from the carcass and before packaging. Theycan be washed by submersion or spraying, or transported in a flumeincluding the disinfection composition. They can be contacted with adisinfection composition according to the invention in a giblet chilleror ice chiller.

The carcass, meat product, carcass portion, carcass side product, or thelike can be packaged before sending it to more processing, to anotherprocessor, into commerce, or to the consumer. Any such product can bewashed with a water based disinfection composition, which can then beremoved (e.g., drained, blown, or blotted) from the poultry. In certaincircumstances wetting the carcass before packaging is disadvantageous.In such circumstances, a gaseous or densified fluid form of thedisinfection composition can be employed for reducing the microbialburden on the carcass. Such a gaseous composition can be employed in avariety of processes known for exposing a carcass to a gas before orduring packaging, such as modified atmosphere packaging.

The advantageous stability of the disinfection compositions describedherein in such methods, which include the presence of carcass debris orresidue, makes these compositions competitive with cheaper, less stable,and potentially toxic chlorinated compounds. Preferred methods of thepresent invention include agitation or sonication of the usecomposition, particularly as a concentrate is added to water to make theuse composition. Preferred methods include water systems that have someagitation, spraying, or other mixing of the solution. The carcassproduct can be contacted with the compositions described hereineffective to result in a reduction significantly greater than isachieved by washing with water, or at least a 50% reduction, preferablyat least a 90% reduction, more preferably at least a 99% reduction inthe resident microbial preparation.

The present methods require a certain minimal contact time of thecomposition with food product for occurrence of significant disinfectioneffect. The contact time can vary with concentration of the usecomposition, method of applying the use composition, temperature of theuse composition, amount of soil and/contamination on the food product,number of microorganisms on the food product, type of disinfectionagent, or the like. Preferably the exposure time is at least about 5 toabout 15 seconds.

Spraying

A preferred method for carcass washing employs a pressure spray of thedisinfection composition. During application of the spray solution onthe food product, the surface of the product can be moved withmechanical action, preferably agitated, rubbed, brushed, etc. Agitationcan be by physical scrubbing of the meat product (e.g., poultrycarcass), through the action of the spray solution under pressure,through sonication, or by other methods. Agitation increases theefficacy of the spray solution in killing micro-organisms, perhaps dueto better exposure of the solution into the crevasses or small coloniescontaining the micro-organisms. The spray solution, before application,can also be heated to a temperature of about 15° to 60° C., preferablyabout 20° C., to increase efficacy.

Application of the material by spray can be accomplished using a manualspray wand application, an automatic spray of food product moving alonga production line using multiple spray heads to ensure complete contactor other spray means. One preferred automatic spray application involvesthe use of a spray booth. The spray booth substantially confines thesprayed composition to within the parameter of the booth. For example,in poultry processing, the production line moves the poultry productthrough the entryway into the spray booth in which the poultry productis sprayed on all its exterior surfaces with sprays within the booth.After a complete coverage of the material and drainage of the materialfrom the poultry product within the booth, the poultry product can thenexit the booth in a fully treated form. The spray booth can includesteam jets that can be used to apply the antimicrobial compositions ofthe invention. These steam jets can be used in combination with coolingwater to ensure that the treatment reaching the poultry product surfaceis less than 65° C., preferably less than 60° C. The temperature of thespray on the poultry product is important to ensure that the poultryproduct is not substantially altered (cooked) by the temperature of thespray. The spray pattern can be virtually any useful spray pattern.

Immersing

Immersing a food product in a liquid disinfection composition can beaccomplished by any of a variety of methods known to those of skill inthe art. During processing of, for example, a poultry product, thepoultry product can be immersed into a tank containing a quantity ofwashing solution containing disinfection agent. The washing solution ispreferably agitated to increase the efficacy of the solution and thespeed in which the solution reduces micro-organisms accompanying thefood product. Agitation can be obtained by conventional methods,including ultrasonics, aeration by bubbling air through the solution, bymechanical methods, such as strainers, paddles, brushes, pump drivenliquid jets, or by combinations of these methods. The disinfection agentcan be heated to increase the efficacy of the solution in killingmicro-organisms. After the food product has been immersed for a timesufficient for the desired effect, the food product can be removed fromthe bath or flume and the disinfection composition can be rinsed,drained, or evaporated off the food product. It is preferable that thepoultry product be immersed in the washing solution after the poultryproduct have been eviscerated.

Foam Treating

In another alternative embodiment of the present invention, the foodproduct can be treated with a foaming version of the disinfectioncomposition. The foam can be prepared by mixing foaming surfactants withthe disinfection agent or composition at time of use. The foamingsurfactants can be nonionic, anionic, or cationic in nature. Examples ofuseful surfactant types include, but are not limited to the following:alcohol ethoxylates, alcohol ethoxylate carboxylate, amine oxides, alkylsulfates, alkyl ether sulfate, sulfonates, quaternary ammoniumcompounds, alkyl sarcosines, betaines and alkyl amides. The foamingsurfactant is typically mixed at time of use with the disinfection agentor composition. At time of use, compressed air can be injected into themixture, then applied to the food product surface through a foamapplication device such as a tank foamer or an aspirated wall mountedroamer.

Gel Treating

In another alternative embodiment of the present invention, the foodproduct can be treated with a thickened or gelled version of thedisinfection agent. In the thickened or gelled state the disinfectionagent remains in contact with the food product surface for longerperiods of time, thus increasing the antimicrobial efficacy. Thethickened or gelled solution will also adhere to vertical surfaces. Thecomposition can be thickened or gelled using existing technologies suchas: xanthan gum, polymeric thickeners, cellulose thickeners or the like.Rod micelle forming systems such as amine oxides and anionic counterions could also be used. The thickeners or gel forming agents can beused either in the concentrated product or mixing with the disinfectionagent, at time of use. Typical use levels of thickeners or gel agentsrange from about 100 ppm to about 10 wt-%.

Light Treating Poultry

In another alternative embodiment of the present invention, the foodproduct can be exposed to an activating light (or other electromagneticradiation) source following application of the disinfection agent. Theactivating light (or other electromagnetic radiation) can improve theefficacy of the disinfecting agent. The light can be ultraviolet light,infrared light, visible light, or a combination thereof. Other forms ofelectromagnetic radiation include radar and microwave.

Disinfection Agent

The disinfection agents utilized in the methods described herein areeffective for killing one or more of the food-borne pathogenic bacteriaassociated with meat, particularly poultry, such as Salmonellatyphimurium, Campylobacter jejuni, Listeria monocytogenes, andEscherichia coli, and the like. The disinfection compositions andmethods of the present invention have activity against a wide variety ofmicroorganisms such as Gram positive (for example, Listeriamonocytogenes) and Gram negative (for example, Escherichia coli)bacteria, yeast, molds, bacterial spores, viruses, etc. The compositionsand methods of the present invention, as described above, have activityagainst a wide variety of human pathogens. The compositions and methodscan kill a wide variety of microbes on the surface of meat, e.g.poultry, or in water used for washing or processing of meat, e.g.,poultry.

In several embodiments, reducing pathogen contamination in carcassprocessing is accomplished by using a non-oxidizing, acidic, buffereddisinfectant that functions efficiently in high temperature, highorganic load, aqueous environments. Preferably, the disinfectantoperates at a low pH, for example around about pH 1 to about pH 4. Morepreferably, the disinfectant is a food safe additive (GRAS). Such adisinfectant can be utilized in several target steps of carcassprocessing, such as in scald-tanks, in rinse and/or dip systems, and inimmersion chillers.

The preferred compositions include concentrate compositions and usecompositions. Typically, a disinfection concentrate composition can bediluted, for example with water, to form a disinfection use composition.In a preferred embodiment, the concentrate composition is diluted intowater employed for scalding, washing, chilling, or otherwise processingpoultry.

Acidic Buffered and Acidic Buffered Copper Containing Disinfectants

Disinfectants within the scope of the invention includemultiple-component disinfection agents. In one embodiment, themultiple-component disinfection agent is a buffered acidic disinfectionagents. The disinfection agent can be a buffered acid solution of astrong acid and a salt of a strong acid and strong base (e.g., TaskerClear). Exemplary acidic agents include those provided in Table 1.Exemplary buffering systems include corresponding salts.

For example, a buffered acidic disinfection agent for use in the methodsdescribed herein can be formed by reacting 98% sulfuric acid with a26-28% by weight ammonium sulfate in water solution (order of additionis ammonium sulfate solution to sulfuric acid) at approximately 300-350°F. for 24 hours, where electrolysis of the reacting solution is appliedfor 1 hour at the start of the process, with a stabilization step(addition of more ammonium sulfate solution to ensure that the reactionis complete) after overnight cooling. As another example, the sameprocess can be performed but at approximately 200-210° F. for 2 hourswith a stabilization step immediately after the 1 hour electrolysisperiod. As a further example, a buffered acidic disinfection agent foruse in the methods described herein can be formed, in a “cold process”,by adding 98% sulfuric acid slowly to a 30% by weight ammonium sulfatesolution, with no stabilization step, at a temperature of 150-200° F.during the addition process. As yet another example, a buffered acidicdisinfection agent for use in the methods described herein can be formedby reacting 8% sulfuric acid with a 26-28% by weight sodium sulfate inwater (order of addition is sodium sulfate solution to sulfuric acid)for 4 hours at approximately 300-350° F. with a stabilization step(addition of more sodium sulfate solution to ensure that the reaction iscomplete) after cooling, where electrolysis of the reacting solution isapplied for 1 hour at the start of the process. In still anotherexample, a buffered acidic disinfection agent for use in the methodsdescribed herein can be formed, in a “cold process” (i.e., noelectrolysis step), by reacting 98% sulfuric acid with a 26-28% byweight sodium sulfate in water solution for 4 hours at approximately300-350° F. with a stabilization step after cooling.

In another embodiment, the multiple-component disinfection agent is abuffered acidic agent in combination with an antimicrobialmetal-containing agent capable of providing free metal ions in solution.The multiple-component disinfection agent can be as described in, forexample, U.S. Pat. No. 7,192,618; U.S. Patent Publication No.2005/0191365 (U.S. applicatoin Ser. No. 11/065,678); and U.S.application Ser. No. 11/674,588, each of which are incorporated hereinby reference. Examples of such antimicrobial metals include copper,zinc, magnesium, silver, and iron. Preferably, the multiple-componentdisinfection agent is a buffered acidic agent in combination with acopper containing agent capable of providing free copper ions insolution. Examples of various copper-containing agents include coppermetal (inorganic copper), cuprous sulfate, cupric sulfate, and coppersulfate pentahydrate. The copper-containing buffered acidic disinfectionagent for use in the methods described herein can be formed by theaddition of various forms of copper to the various forms of acidicbuffered disinfection composition described above.

In yet another embodiment, the multiple-component disinfection agent isan acidic agent in combination with a buffer, a sulfate-containingagent, and a copper-containing agent and capable of providing freecopper ions in solution. In some embodiments, a single agent can deliverboth copper ions and sulfate, for example copper sulfate. Such a mixtureproduces a copper sulfate complex that is highly protonated and at a lowpH. Further, the sulfate component is thought to enhance copper andproton uptake by microbes. For example, a copper-containing bufferedacidic disinfection agent, also containing sulfate, can be formed bymixing water (about 68%), one of the acidic buffered disinfectioncompositions described above (about 12%), and copper sulfatepentahydrate (about 20%) (e.g., Tasker Blue®). This low pH (bufferedinorganic acidic) solution serves as the active (e.g., ionic Cu2+ form)carrier of copper.

The various copper-containing buffered acidic disinfection agents (e.g.,Tasker Blue®) can be used in combination with additional buffered acidicdisinfection agents (e.g., Tasker Clear) to achieve the prescribed pHcontrol and copper content of the treatment solution. For example, theTasker Clear product can be used for pH control, while the Tasker Blue®product can be used for copper control-these products can be addedseparately or in a pre-formulated blend of Clear® and Blue® to water toachieve the desired pH range (e.g., pH 1.5-3) and the desired copperrange (e.g., 1-20 ppm). Water testing can be performed to determine theconcentrations of Clear® and Blue® to add to achieve the desiredtargets.

Also preferable is that each of the disinfection agent ingredients aregenerally recognized as safe (GRAS) and are permitted for use as directhuman food ingredients using good manufacturing practice.

Disinfectants described above can be produced in accord with the methodsand formulations as described in U.S. patent application Ser. No.10/922,604 (published as US 2005/0191394 A1); U.S. patent applicationSer. No. 11/065,678 (published as US 2005/0191365 A1); U.S. Pat. No.5,989,595; U.S. Pat. No. 6,242011B1; and U.S. Pat. No. 7,192,618, eachof which are incorporated herein by reference. Generally, an effectiveacidic copper containing disinfectant agent can be made by combining anacid, a buffer, and a copper containing substance so as to reach a pH ofabout 1 to about 4 and a copper concentration of about 1 ppm to about 20ppm, preferably about 3 ppm. For example, an acid, a buffer, and acopper containing substance can be combined in equal measure in a vesselat room temperature so as to reach a pH of about 2 and a copperconcentration of about 3 ppm.

TABLE 1 Acids Generally Recognized as Safe (GRAS) Acid Name CAS No.ACETIC ACID 000064-19-7 ACONITIC ACID 000499-12-7 ADIPIC ACID000124-04-9 ALGINIC ACID 009005-32-7 P-AMINOBENZOIC ACID 000150-13-0AMINO TRI(METHYLENE PHOSPHONIC ACID), 020592-85-2 SODIUM SALT ANISICACID 001335-08-6 ASCORBIC ACID 000050-81-7 L-ASPARTIC ACID 000056-84-8BENZOIC ACID 000065-85-0 N-BENZOYLANTHRANILIC ACID 000579-93-1 BORICACID 010043-35-3 (E)-2-BUTENOIC ACID 003724-65-0 BUTYRIC ACID000107-92-6 CHOLIC ACID 000081-25-4 CINNAMIC ACID 000621-82-9 CITRICACID 000077-92-9 CYCLOHEXANEACETIC ACID 005292-21-7CYCLOHEXANECARBOXYLIC ACID 000098-89-5 DECANOIC ACID 000334-48-55-DECENOIC ACID 085392-03-6 6-DECENOIC ACID 085392-04-7 9-DECENOIC ACID014436-32-9 (E)-2-DECENOIC ACID 000334-49-6 4-DECENOIC ACID 026303-90-2DEHYDROACETIC ACID 000520-45-6 DESOXYCHOLIC ACID 000083-44-32,4-DIHYDROXYBENZOIC ACID 000089-86-1 3,7-DIMETHYL-6-OCTENOIC ACID000502-47-6 2,4-DIMETHYL-2-PENTENOIC ACID 066634-97-7 ERYTHORBIC ACID000089-65-6 2-ETHYLBUTYRIC ACID 000088-09-5 4-ETHYLOCTANOIC ACID016493-80-4 FOLIC ACID 000059-30-3 FORMIC ACID 000064-18-6 FUMARIC ACID000110-17-8 GERANIC ACID 000459-80-3 GIBBERELLIC ACID 977136-81-4D-GLUCONIC ACID 000526-95-4 L-GLUTAMIC ACID 000056-86-0 GLUTAMIC ACIDHYDROCHLORIDE 000138-15-8 GLYCOCHOLIC ACID 000475-31-0 HEPTANOIC ACID000111-14-8 (E)-2-HEPTENOIC ACID 018999-28-5 HEXANOIC ACID 000142-62-1TRANS-2-HEXENOIC ACID 013419-69-7 3-HEXENOIC ACID 004219-24-3HYDROCHLORIC ACID 007647-01-0 4-HYDROXYBENZOIC ACID 000099-96-74-HYDROXYBUTANOIC ACID LACTONE 000096-48-0 4-HYDROXY-2-BUTENOIC ACIDGAMMA-LACTONE 000497-23-4 5-HYDROXY-2,4-DECADIENOIC ACID 027593-23-3DELTA-LACTONE 5-HYDROXY-2-DECENOIC ACID DELTA-LACTONE 051154-96-25-HYDROXY-7-DECENOIC ACID DELTA-LACTONE 025524-95-24-HYDROXY-2,3-DIMETHYL-2,4-NONADIENOIC 000774-64-1 ACID GAMMA LACTONE6-HYDROXY-3,7-DIMETHYLOCTANOIC ACID 000499-54-7 LACTONE(Z)-4-HYDROXY-6-DODECENOIC ACID LACTONE 018679-18-05-HYDROXY-2-DODECENOIC ACID LACTONE 016400-72-91-HYDROXYETHYLIDENE-1,1-DIPHOSPHONIC ACID 002809-21-42-(2-HYDROXY-4-METHYL-3- 057743-63-2 CYCLOHEXENYL)PROPIONIC ACIDGAMMA-LACTONE 4-HYDROXY-4-METHYL-7-CIS-DECANOIC ACID 070851-61-5GAMMALACTONE 5-HYDROXY-4-METHYLHEXANOIC ACID DELTA- 010413-18-0 LACTONE4-HYDROXY-4-METHYL-5-HEXENOIC ACID GAMMA 001073-11-6 LACTONE4-HYDROXY-3-METHYLOCTANOIC ACID LACTONE 039212-23-2 HYDROXYNONANOICACID, DELTA-LACTONE 003301-94-8 3-HYDROXY-2-OXOPROPIONIC ACID001113-60-6 4-HYDROXY-3-PENTENOIC ACID LACTONE 000591-12-85-HYDROXYUNDECANOIC ACID LACTONE 000710-04-3 5-HYDROXY-8-UNDECENOIC ACIDDELTA- 068959-28-4 LACTONE ISOBUTYRIC ACID 000079-31-2 ISOVALERIC ACID000503-74-2 ALPHA-KETOBUTYRIC ACID 000600-18-0 LACTIC ACID 000050-21-5LAURIC ACID 000143-07-7 LEVULINIC ACID 000123-76-2 LIGNOSULFONIC ACID008062-15-5 LINOLEIC ACID 000060-33-3 L-MALIC ACID 000097-67-6 MALICACID 000617-48-1 2-MERCAPTOPROPIONIC ACID 000079-42-5 2-METHOXYBENZOICACID 000579-75-9 3-METHOXYBENZOIC ACID 000586-38-9 4-METHOXYBENZOIC ACID000100-09-4 TRANS-2-METHYL-2-BUTENOIC ACID 000080-59-1 2-METHYLBUTYRICACID 000116-53-0 3-METHYLCROTONIC ACID 000541-47-9 2-METHYLHEPTANOICACID 001188-02-9 2-METHYLHEXANOIC ACID 004536-23-6 5-METHYLHEXANOIC ACID000628-46-6 4-METHYLNONANOIC ACID 045019-28-1 4-METHYLOCTANOIC ACID054947-74-9 3-METHYL-2-OXOBUTANOIC ACID 000759-05-73-METHYL-2-OXOPENTANOIC ACID 001460-34-0 4-METHYL-2-OXOPENTANOIC ACID000816-66-0 3-METHYLPENTANOIC ACID 000105-43-1 4-METHYLPENTANOIC ACID000646-07-1 2-METHYL-2-PENTENOIC ACID 003142-72-1 2-METHYL-3-PENTENOICACID 037674-63-8 2-METHYL-4-PENTENOIC ACID 001575-74-24-METHYLPENT-2-ENOIC ACID 010321-71-8 3-METHYL-3-PHENYL GLYCIDIC ACID000077-83-8 ETHYL ESTER 4-(METHYLTHIO)-2-OXOBUTANOIC ACID 000583-92-62-METHYLVALERIC ACID 000097-61-0 MYRISTIC ACID 000544-63-8 NONANOIC ACID000112-05-0 (E)-2-NONENOIC ACID 014812-03-4 2-NONENOIC ACIDGAMMA-LACTONE 021963-26-8 9,12-OCTADECADIENOIC ACID (48%) AND 9,12,15-977043-76-7 OCTADECATRIENOIC ACID (52%) OCTANOIC ACID 000124-07-2(E)-2-OCTENOIC ACID 001871-67-6 OLEIC ACID 000112-80-1 3-OXODECANOICACID GLYCERIDE 128331-45-3 3-OXODODECANOIC ACID GLYCERIDE 128362-26-53-OXOHEXADECANOIC ACID GLYCERIDE 128331-46-4 3-OXOHEXANOIC ACIDDIGLYCERIDE 977148-06-3 3-OXOOCTANOIC ACID GLYCERIDE 128331-48-62-OXOPENTANEDIOIC ACID 000328-50-7 2-OXO-3-PHENYLPROPIONIC ACID000156-06-9 3-OXOTETRADECANOIC ACID GLYCERIDE 128331-49-7 PALMITIC ACID000057-10-3 4-PENTENOIC ACID 000591-80-0 2-PENTENOIC ACID 013991-37-2PERACETIC ACID 000079-21-0 PERIODIC ACID 010450-60-9 PHENOXYACETIC ACID000122-59-8 PHENYLACETIC ACID 000103-82-2 3-PHENYLPROPIONIC ACID000501-52-0 PHOSPHORIC ACID 007664-38-2 POLY(ACRYLICACID-CO-HYPOPHOSPHITE), 071050-62-9 SODIUM SALT POLYACRYLIC ACID, SODIUMSALT 009003-04-7 POLYMALEIC ACID 026099-09-2 POLYMALEIC ACID, SODIUMSALT 030915-61-8 POTASSIUM ACID PYROPHOSPHATE 014691-84-0 POTASSIUM ACIDTARTRATE 000868-14-4 PROPIONIC ACID 000079-09-42-(4-METHYL-2-HYDROXYPHENYL)PROPIONIC 065817-24-5 ACID-GAMMA-LACTONEPYROLIGNEOUS ACID 008030-97-5 PYRUVIC ACID 000127-17-3 SALICYLIC ACID000069-72-7 SODIUM ACID PYROPHOSPHATE 007758-16-9 SODIUM BISULFATE(SODIUM ACID SULFATE) SORBIC ACID 000110-44-1 STEARIC ACID 000057-11-4SUCCINIC ACID 000110-15-6 SULFAMIC ACID 005329-14-6 SULFURIC ACID007664-93-9 SULFUROUS ACID 007782-99-2 TANNIC ACID 001401-55-4 TARTARICACID, L 000087-69-4 TAUROCHOLIC ACID 000081-24-31,2,5,6-TETRAHYDROCUMINIC ACID 056424-87-4 THIOACETIC ACID 000507-09-5THIODIPROPIONIC ACID 000111-17-1 TRIFLUOROMETHANE SULFONIC ACID001493-13-6 (2,6,6-TRIMETHYL-2- 015356-74-8HYDROXYCYCLOHEXYLIDENE)ACETIC ACID GAMMA-LACTONE UNDECANOIC ACID000112-37-8 10-UNDECENOIC ACID 000112-38-9 N-UNDECYLBENZENESULFONIC ACID050854-94-9 VALERIC ACID 000109-52-4 VANILLIC ACID 000121-34-6

Application Amounts of Acid/Sulfate Disinfection Agents

Generally, the longer the contact time with the meat surface, the higherthe pH should be in order to minimize organoleptic damage. Conversely,shorter contact times allow a lower pH for better microbial reductions.For example, depending upon the contact time, the pH can be about 1.0,about 1.5, about 2.0, about 2.5, about 3.0, about 3.5, or about 4.0.Each application dosage is a function of effectiveness and cost. As thepH is a logarithmic scale, nearly 10 times more disinfectant is requiredto reach a pH of 2.0 as needed to reach a pH of 3.0.

Where the disinfection agent comprises an acidic buffered disinfectionagent/composition, the actual application requirement is generally afunction of the alkalinity of the processing plant water. Thedisinfectant is titrated until reaching the target pH, then monitoredand maintained.

In those embodiments containing a buffered acid and an antimicrobialmetal, the actual application requirement is generally a function of thedesired target pH and the desired metal concentration. Preferably, thescalder, rinse, or bath solution contains an amount of addeddisinfection composition containing acid, buffer, and copper (e.g.,Tasker Blue®) so as to reach a pH of about 1.5 to about 4.0 and a coppercontent of about 2 ppm to about 20 ppm. The pH can be adjustedindependently by further addition of a disinfection compositioncontaining acid and buffer (e.g., Tasker Clear).

Generally, the effectiveness of copper is highest at low pH; as the pHrises, the copper becomes bound and less effective. Preferably, theactive, unbound copper concentration is about 2 ppm to about 4 ppm, morepreferably about 3 ppm. To counter the risk of copper being bound, thedisinfectant can be added up to about 20 ppm. Concentrations above thislevel should be avoided so as to minimize the risk of leaving residueson the carcasses. For example, depending on the pH, contact time, andthe risk of copper being bound, the copper content of the scalder tankcan be about 1 ppm, about 1.5 ppm, about 2 ppm, about 2.5 ppm, about 3ppm, about 3.5 ppm, about 4 ppm, about 4.5 ppm, about 5 ppm, about 5.5ppm, about 6 ppm, about 7 ppm, about 8 ppm, about 10 ppm, about 12 ppm,about 14 ppm, about 16 ppm, about 18 ppm, or about 20 ppm. For example,disinfectant can be added to the scalder water so as to reach a pH ofabout 2.0 and a copper content of about 3 ppm.

As a further example, poultry processing water containing disinfectingagent can about 98-99% water; about 0.1-0.5% copper sulfate, about0.1-0.5% sulfuric acid; and about 0.1-0.5% ammonium sulfate. Such a washcan have a pH of about 2-3; a specific gravity at 25° C. of 1.002 orapproximately 1.002; a boiling point of 212° F. or approximately 212°F.; and a freezing point of 32° F. or approximately 32° F.

The acidic buffered metal-containing disinfectants (especially thecopper and sulfate containing formulations) are very effective at lowconcentrations and short exposure times. An effective killing Dose isusually measured as Concentration x Time (D=C×T). Generally,antimicrobial chemicals are used at concentrations in the 10's to 100'sof ppm up to a full percentage range, and often for many minutes up toseveral hours, in order to be effective. The effective dose of thevarious above disinfectants for antimicrobial effect is much lower.

It is known that sulfate (SO₄ ²⁻), copper (Cu²⁺), and the ammonium ion(NH⁴⁺) are used by bacteria as part of their normal nutritionalrequirements. It is also known that at high concentrations coppersulfate can be used for plant disease control, as it is an effectiveantifungal agent, and will also control algae growth in lakes and ponds.The presence of sulfate, copper, and the low pH due to the presence ofsulfuric acid provide the above disinfectant its antimicrobialproperties.

The acidic buffered copper-containing disinfectant is non-oxidizing.This is in sharp contrast to other antimicrobial chemicals, such aschlorine compounds, ozone, and peracetic acid. Because it isnon-oxidizing the disinfectant can be used in water based environments,such as the scald tank or chill tank used in poultry processing, wherethere is a significant amount of suspended or dissolved organic matter,without its effectiveness being impaired. Also, it will not produceoxidized compounds that will impart off-odors and flavors to the productor create toxic by-products such as tri-halomethanes (THM's). And, itwill not cause the corrosion to plant and equipment typical of oxidizingchemicals.

Antimicrobial chemicals that are non-oxidizing are usually organicacids, such as lactic acid, or a combination of acids. Unlike thedisinfectant containing sulfuric acid, ammonium sulfate, and coppersulfate, these organic acids are usually only effective at highconcentrations, creating low pH environments where the organic acidmolecules are in their undissociated, non-ionize state. In this form andconcentration, the organic acid can pass through the cell membrane andgain entrance into the cell. Once inside the cell, the naturally higherpH of the cell will cause the acid to ionize and release protons(hydrogen ions). This will lower the internal pH of the cell. Ascellular processes will only function optimally with the internal pH ina narrow range close to neutrality (pH 7), internal “proton pumps” areused to remove the unwanted protons from the cell. This process requiresthe use of energy (ATP). Bacterial cell growth therefore becomesinhibited due to a depletion of cellular ATP and reduced metabolicactivity, as long as it remains in a low pH environment and in thepresence of these organic acids.

While under no obligation to provide a mechanism of action, thefollowing is the currently understood mechanism of action for thedisinfectant containing sulfuric acid, ammonium sulfate, and coppersulfate pentahydrate. Such mechanistic explanation is not intended inany way to limit the invention described herein. It is known thatsulfate is required for growth of the microbial cell. It provides thecell's requirement for sulfur for the formation of the sulfur containingamino acids cysteine, cystine, and methionine, which in turn arerequired for the synthesis of structural and enzymatic proteins. Thebacteria have a well understood process that “actively transports”sulfate into the cell. Thus, in a complex environment bacterial cellswill scavenge for sulfate in order to grow. The disinfectant containingbuffered acid, sulfate, and copper exploits the sulfate ion scavengingfunction of bacterial cells.

The sulfate of the multi-component disinfectant is transported into thecell via the sulfate transport pathway and carries with it protons andcopper ions. Once inside the cell, the protons are released and have tobe removed via the energy consuming “proton pump.” In addition, theexcess copper is now made available to bind to disulphide (—S—S—) and/orsulphydryl groups (—SH) associated with proteins. Interference withthese groups can denature the proteins and destroy their structural orenzymatic activities, leading to the inhibition of cellular processes.Thus, there are several anti-microbial activities working in concertleading to the death of the cell: a depletion of ATP required for theremoval of protons and the inactivation of structural and enzymaticproteins required for molecular synthesis.

Other Agents

In various embodiments, the method of the present invention employ acomposition including peroxyacetic acid. Peroxyacetic (or peracetic)acid is a peroxycarboxylic acid having the formula: CH₃COOOH. Generally,peroxyacetic acid is a liquid having an acrid odor at higherconcentrations and is freely soluble in water, alcohol, ether, andsulfuric acid. Peroxyacetic acid can be prepared through any number ofmethods known to those of skill in the art including preparation fromacetaldehyde and oxygen in the presence of cobalt acetate. A solution ofperoxyacetic acid can be obtained by combining acetic acid with hydrogenperoxide. A 50% solution of peroxyacetic acid can be obtained bycombining acetic anhydride, hydrogen peroxide and sulfuric acid. Othermethods of formulation of peroxyacetic acid include those disclosed inU.S. Pat. No. 2,833,813, which is incorporated herein by reference.

In some embodiments, the disinfection agent is any one or more of themulti-purpose acid compositions (e.g., a peroxyacetic acid-baseddisinfection agent) of U.S. Pat. No. 6,375,976, incorporated herein byreference. This disinfection agent is an acidic composition with a pH ofless than 1, and is non-caustic to human tissue and safe for humaningestion. Such agent includes, for example, Inspexx® (Ecolab).

The peroxyacetic acid disinfection composition can be utilized in thevarious processing steps and systems described herein. For example, theperoxyacetic acid disinfection composition can be used in the scalder ata concentration of about 2 to about 50 ppm, preferably about 30 ppm. Asanother example, the peroxyacetic acid disinfection composition can beused in a dress rinsing at a concentration of about 50 to about 300 ppm,preferably about 200 ppm. As a further example, the peroxyacetic aciddisinfection composition can be used in an inside-outside bird wash at aconcentration of about 20 to about 200 ppm, preferably about 50 to about100 ppm. As yet another example, the peroxyacetic acid disinfectioncomposition can be used in a spray rinse at a concentration of about 50to about 300 ppm, preferably about 100 to about 200 ppm. In a stillfurther example, the peroxyacetic acid disinfection composition can beused in submersion chilling at a concentration of about 2 to about 100ppm, preferably about 2 to about 30 ppm.

In another embodiment, the disinfection agent comprises phosphoric acid,hydrochloric acid, and citric acid (e.g., FreshFx®, SteriFx). Forexample, the Sterifx FreshFx® antimicrobial solutions comprise less than5 wt % of each of phosphoric acid (CAS No. 7664-38-2), hydrochloric acid(CAS No. 7647-01-0), and citric acid (CAS No. 77-92-9). See e.g., Ingramet al, Southern Poultry Science Society Meeting Abstracts. Oct. 13,2002, incorporated herein by reference in its entirety.

Amount Applied

In various embodiments, contacting the disinfection agent with the foodproduct is accomplished with a quantity of antimicrobial agentsufficient to acceptably reduce the microbial burden in one or morestages of processing. In certain embodiments, contacting thedisinfection agent with the food product at several stages of processingproduces enhanced and/or synergistic reduction in microbial burden onthe food product. The level of disinfection agent required for a desiredeffect can be determined by any of several methods. For example, foodproduct samples can each be exposed to different amounts of disinfectionagent. Then the food product samples can be evaluated for the amount ofdisinfection agent that yields the desired antimicrobial effect, and,preferably, for desired organoleptic qualities. The amount ofdisinfection agent required for antimicrobial effect at each processingstage can be reduced by application at several stages. Such a titrationwith disinfection agent can be conducted at several amounts of ortreatment times in combination with treatment or exposure at otherstages of processing, yielding a matrix of treatment results. Such amatrix yields a quantitative assessment of the amount of antimicrobialtreatment required at various stages of processing to achieve a desiredantimicrobial effect, and, optionally, desired organoleptic qualities.Synergy can be evaluated from such matrices using methods known to thoseof skill in the art.

The concentration of various disinfection agent can be as discussedabove. Alternatively, the amount of disinfection agent added to scalderwater can be the maximal amount approved by the Food and DrugAdministration for a particular application, or some fraction thereof(e.g., about 50% -95%). As an example, the amount of disinfection agentadded to scalder water is the 95%, 90%, 85%, 80%, 75%, 70%, 65%, 60%,55%, or 50%, or less, of the maximal amount approved by the Food andDrug Administration for a particular application.

Processing Carcass Wash Water

Washing meat products can employ a large volume of water, or anothercarrier. Meat wash water can be used more than once (recycled), providedthe water can be treated so that it does not transfer undesirablemicrobes to the meat being washed with the recycled wash water. One wayto prevent the transfer of such undesirable microbes, is to reduce themicrobial burden of the recycled wash water by adding one or moredisinfection agents described herein. For example, if the fluid to berecycled is water-based and lacking any disinfection agent, adisinfection agent concentrate composition can be added to result in aneffective antimicrobial concentration in the fluid to be recycled.Alternatively, if the fluid to be recycled already includes or hasincluded a disinfection agent, a disinfection agent concentratecomposition can be added to increase any concentration of disinfectionagent to an effective antimicrobial level. It may be that thedisinfection agent in the solution to be recycled has been totallydepleted, in which case more of the disinfection agent composition isadded.

In some circumstances, the water to be recycled includes a substantialburden of organic matter or microbes. If this is the case, the water maybe unsuitable for direct recycling. However, if the water is to berecycled, a sufficient quantity of the disinfection agent compositioncan be added to provide an effective antimicrobial amount of thedisinfection agent after a certain amount is consumed by the organicburden or microbes already present. Then, the recycled fluid can be usedwith disinfection effect. Routine testing can be employed fordetermining levels of disinfection agent, or of organic burden.

In the case of poultry processing, the method of recycling the poultrywash water includes recovering the poultry wash water, adding acomposition of disinfection agent, and reusing the poultry wash waterfor washing poultry, for example, as described above. The poultry washwater can be recovered from steps in poultry processing includingsubmersion scalding, dress rinsing, inside-outside bird washing, sprayrinsing, and submersion chilling. Methods of recovering wash water fromthese steps are well-known to those skilled in the poultry washingand/or processing arts. The wash water can also be strained, filtered,diluted, or otherwise cleaned or processed during recycling. These stepscan be modified for the corresponding steps for the processing of othermeat products.

FIG. 1A provides an overview of an animal carcass processing system, thesteps of which include:

Live Receiving and Hanging: Microorganism contamination is a concern atany of these steps. During live receiving and hanging, microorganismcontamination can overload interventional controls in the system and canbe carried forward to subsequent steps;

Immobilization and Bleeding: During immobilization and bleeding, voidingof feces can further contaminate the animal carcass which can further becarried forward to subsequent steps in the system;

Scalding: While the scalding process removes much of the dirt and fecescontamination, microorganisms accumulate in the bath during multiplescalding processing steps. Thus, cross-contamination is increasinglikely as multiple processes are completed;

Feather, Hair, Skin Removal: Similar to the scalding process, theapparatus which picks feathers, plucks hair, removes skin, and similarapparatus are implicated in cross-contamination of animal carcasses.Likewise, cross-contamination is increasingly likely as multipleprocesses are completed;

Sanitization: Some processes use a sanitization step to treat animalcarcasses with a sanitizing agent (e.g., chlorine in a “New York” rinsein poultry) to provide some anti-microbial action; and

Evisceration and Chilling: Animal carcass rupture and spillage duringthe evisceration step contaminates the animal carcasses and equipment.Chilling, especially by immersion, is a cause of cross-contamination.

FIG. 1B depicts another alternative of a microorganism interventionsystem according to the present invention. Stations 1-5 are points wheremicrobial intervention can occur both individually and in combinationwith other stations. An antimicrobial agent used in the Sanitizationstation (shown as station 5) can be reused in the Scalding station(station 1), the Feather Removal station (station 3) and intermediatestations (stations 2 and 4). An antimicrobial agent used at station 5can also be reused at station 5. The bold arrows show the direction ofanimal carcass through the system. The narrow arrows show the flowdirection of an antimicrobial agent through the system. Bidirectionalarrows depict a flow direction which can be reversible or circular.Dashed arrows depict that the same or different processes can occurbefore station 1 and after station 5.

FIG. 2 depicts another alternative of a microorganism interventionsystem according to the present invention. Stations 1-7 are points wheremicrobial intervention can occur both individually and in combinationwith other stations. An antimicrobial agent used in the Sanitizationstation (shown as station 5) can be reused in the Scalding station(station 1), the Feather Removal station (station 3), the Evisceratingstation and the Chilling station (collectively shown as station 7) andintermediate stations (stations 2, 4 and 6). An antimicrobial agent usedat station 5 can also be reused at station 5. The arrows show the flowdirection of an antimicrobial agent through the system. Bidirectionalarrows depict a flow direction which can be reversible or circular.Dashed arrows depict that the same or different processes can occurbefore station 1 and after station 7.

In one embodiment as depicted in FIG. 1B, the antimicrobial agent can bea liquid which can be applied by spraying on a carcass. Excess microbialagent can be removed from the carcass, e.g., by falling due to gravity,and the excess can be collected followed by distribution to stations 1-4by suitable means, e.g., pumping. In an alternative, the excessmicrobial agent can be redistributed to station 5 which is sprayed onthe same or another carcass. In certain embodiments where station 5 isenclosed or partially enclosed, the excess microbial agent can becollected through at least one opening in or near the bottom of station5. The excess microbial agent can then be distributed to stations 1-4 bysuitable means, e.g., pumping. In an alternative, the excess microbialagent can be redistributed to station 5 which is sprayed on the same oranother carcass. In yet another embodiment, station 5 can be elevatedabove one or more of stations 1-4. Excess microbial agent can fall bygravity from the carcass directly onto one or more of stations 1-4. Inanother embodiment, station 5 can be elevated above one or more ofstations 1-4, and the excess antimicrobial agent can be collected anddistributed by gravity within an open or closed system, e.g. a guttersystem, to one or more of stations 1-4. In another embodiment, theexcess microbial agent can be collected and stored for a suitable periodof time before distribution.

In an alternative embodiment as depicted in FIG. 2, the antimicrobialagent can be a liquid which can be applied by spraying on a carcass.Excess microbial agent can be removed from the carcass, e.g., by fallingdue to gravity, and the excess can be collected followed by distributionto stations 1-4, 6 and 7 by suitable means, e.g., pumping. In analternative, the excess microbial agent can be redistributed to station5 which is sprayed on the same or another carcass. In certainembodiments where station 5 is enclosed or partially enclosed, theexcess microbial agent can be collected through at least one opening inor near the bottom of station 5. The excess microbial agent can then bedistributed to stations 1-4, 6 and 7 by suitable means, e.g., pumping.In an alternative, the excess microbial agent can be redistributed tostation 5 which is sprayed on the same or another carcass. In anotherembodiment, the excess microbial agent can be collected and stored for asuitable period of time before distribution. In yet another embodiment,station 5 can be elevated above one or more of stations 1-4, 6 and 7.Excess microbial agent can fall by gravity from the carcass directlyonto one or more of stations 1-4, 6 and 7. In another embodiment,station 5 can be elevated above one or more of stations 1-4, 6 and 7,and the excess antimicrobial agent can be collected and distributed bygravity within an open or closed system, e.g. a gutter system, to one ormore of stations 1-4, 6 and 7.

In addition to applying the antimicrobial agent to an animal carcass byspraying, the agent can be applied to the carcass by dipping, brushing,electrostatic spray, and any other suitable means whereby a portion ofthe agent remains on the carcass. In addition to removing the excessantimicrobial agent by gravity, the excess can additionally be removedby applying a centripetal force by rotating a carcass, by suction, e.g.,applying a vacuum to a carcass, and any other suitable means. In each ofthe above embodiments, the excess microbial agent can be used with thesame additional agent and/or mixed with a different antimicrobial agentor combination of antimicrobial agents. The pH and concentration of thesolution applied to the carcass can be adjusted by methods known tothose of skill in the art. Such adjustments can also be accomplished byautomated detection and titration systems known to those of skill in theart. In addition, filters and other clarifying apparatus can be providedat individual or multiple stations within the system or in thedistribution of the antimicrobial agent. Furthermore, stations 2, 4 and,in the case of FIG. 2, station 6 can comprise additional sanitizingmeans, e.g., pressurized liquid sprayers, which can emit the same ordifferent antimicrobial agent or a liquid that does not contain anantimicrobial agent.

Having described the invention in detail, it will be apparent thatmodifications, variations, and equivalent embodiments are possiblewithout departing the scope of the invention defined in the appendedclaims. Furthermore, it should be appreciated that all examples in thepresent disclosure are provided as non-limiting examples.

EXAMPLES

The following non-limiting examples are provided to further illustratethe present invention. It should be appreciated by those of skill in theart that the techniques disclosed in the examples that follow representapproaches the inventors have found function well in the practice of theinvention, and thus can be considered to constitute examples of modesfor its practice. However, those of skill in the art should, in light ofthe present disclosure, appreciate that many changes can be made in thespecific embodiments that are disclosed and still obtain a like orsimilar result without departing from the spirit and scope of theinvention.

Example 1

The effect of using a scalder disinfectant was examined in a poultryscalder alone or in combination with a post-pick dip solution as a meansof reducing pathogenic and indicator populations of bacteria on chickencarcasses. Sets of carcasses (10 per experimental group) were collectedpost-scald and post-pick and dip and evaluated for aerobic plate counts,E. coli counts, and Salmonella prevalence over a period of six weeks ata poultry processing plant.

For the scalder disinfectant treatment groups, all three scalders wereinitially dosed with pHarlo Blue® 0020 (Tasker) to a target level of 38ppm (range: 30-60 ppm) with a target level of 0.8 ppm (range: 0.8-2.0ppm) copper. pH was adjusted to a final pH of 2.0 to 2.2 and recorded.After the initial dose, the third scalder was continually dosed duringthe process with pHarlo Blue® 0020 to a target level of 38 ppm (range:30-60 ppm) with a target level of 0.8 ppm (range: 0.8-2.0 ppm copper).The overflow water coming out of the scalder was monitored for pH andfree copper and the level of material added to the incoming fresh waterwas adjusted based on these measurements.

Additionally, for the scalder and post-pick dip treatment group, apost-scald dip tank was used to treat post-pick carcasses. The dipsolution was made by dosing tap water in a 44 gallon container to a pHof 2.0 and 2.0 ppm copper. Carcasses were removed from the linepost-pick and dipped into the solution for 5-10 seconds. Ten carcasseswere removed post scald and ten were removed post-pick and dip using thefollowing technique to ensure that no bias was introduced.

Carcass selection was the same for all experimental groups. After atleast 2 flocks had traversed the scalder, carcasses were removed postscald using the following technique to ensure that no bias wasintroduced. Carcasses were selected visually on the line post-scald,then the next five carcasses were counted aloud and the sixth carcasswas selected for testing. The individual selecting the carcasses waswearing sterile examination gloves. In this way, no visual cues wereused to introduce bias. Ten selected carcasses for each control andtreatment were thus selected and were then hung on a sanitized rack, andallowed to drip. Sterile zip ties were used to cinch the neck of eachchicken to prevent leakage of crop contents into the sample bag.Additionally, a sterile, unscented tampon was used to plug the vent ofthe chickens to prevent leakage of fecal material into the sample bagduring shaking. In this way, the contents of the intestinal tract werenot able to influence the microbiological effect of the disinfectionability of pHarlo Blue® 0020 during scalding. The carcasses were thenindividually bagged in sterile polyethylene bags and rinsed using 400 mlof sterile Butterfield's phosphate buffer by conducting the wholecarcass rinse method as employed by USDA inspectors in processingfacilities. The rinsate was encoded using a 4 digit number (to preventidentification by ABC employees and the introduction of bias) and senton blue ice in a cooler using FedEx to ABC Research Corporation(Florida) for evaluation for APC, E. coli counts, and Salmonellaprevalence.

These tests were conducted for 6 weeks and a total of 13 complete datasets were collected. Aerobic Plate Counts (APC) were determined usingThe Official Methods of Analysis of the AOAC, Method 990.12, andreported in colony forming units (CFU). E. coli were conducted using TheOfficial Methods of Analysis of the AOAC, Method No. 990.12, andreported in colony forming units (CFU). Salmonella were tested using TheOfficial Methods of Analysis of the AOAC, Method No. 2000.07, andreported as either positive or negative. Main effects of control versustreated were evaluated for each bacterial type. The overall experimentaldesign was a 3×13×3×10 of treatment, day of collection, bacterial typeevaluated, and chicken, for a total of 390 chickens and 1170 tests.Treatment effects were determined using t-tests and the StatisticalAnalytical Software (SAS) program for APC and E. coli counts. ForSalmonella prevalence, Fishers Exact Test was conducted using SAS.

Results showed that use of Tasker Blue® in the scalder and in apost-pick dip solution had a significant (p<0.05) impact on APC (seee.g., FIG. 4, FIG. 5) and E. coli (see e.g., FIG. 6, FIG. 7) counts onchicken carcasses. Similarly, use of Tasker Blue® in the scaldersignificantly impacted Salmonella prevalence values (see e.g., FIG. 8).Such reduction can, later in the process, impact the Salmonella loadcoming out of the chillers. Lesser Salmonella reductions post-pick andpost-dip (as compared to post-scald reductions) may be explained bypossible cross-contamination by the pickers (see e.g., FIG. 9).

These data indicate that scalder disinfectant provides an effectivemeans of lowering total numbers of bacteria, enteric bacteria (E. coli)and Salmonella in particular. The high heat and organic load of thescalder currently precludes the use of other products. Thus, use of adisinfectant, such as Tasker Blue®, in the scalder and/or as a post-pickdip solution can assist processors in meeting the USDA-FSIS SalmonellaPerformance Standard.

Example 2

The effect of decreased scalder temperature in combination with the useof a scalder disinfectant on yield was examined.

Routine problems encountered with lowered scalder temperature includeincreased Salmonella prevalence and Poor picking and epidermis removal.Salmonella's maximum growth temperature is 113° F. Practitioners in theart generally recommend a minimum of 10° F. above the maximum growthtemperature to prevent growth in the scalder. As such, it is routine inthe industry to the maintain the scalder at a minimum temperature of123° F. In a preliminary study where a scalder was maintained at 114°F., Salmonella were observed at a level of 10⁵ (100,000)/ml of scalderwater, resulting in every carcass run through the scalder beinginoculated with Salmonella during scalding.

Collection procedures were as described in Example 1, except asotherwise noted. Control scalder temperatures were 132°, 134°, and 136°F. for the first, second, and third scalder tanks, respectively. Scaldertemperatures the disinfectant treated tanks for carcasses collectedpost-hoc cutter were 113°, 123°, and 138° F. for the first, second, andthird scalder tanks, respectively. Scalder temperatures for thedisinfectant treated tanks for carcasses collected pre-IOBW were 110°,114°, and 134° F. for the first, second, and third scalder tanks,respectively. 100 carcasses from the same flock were collected post-hockcut and divided between a treated line and a control line (see FIG. 12).100 carcasses from the same flock were collected pre-pre inside outsidebird washing (IOBW) and divided between a treated line and a controlline (see FIG. 12). Carcasses were weighed and scalder water assayed forSalmonella. Three replicate trials were conducted for a total of 1200carcasses over 6 flocks.

Results showed reduction of scalder temperatures for post-hock cut (seee.g., FIG. 13) and pre-IOBW (see e.g., FIG. 14) as compared to controlsresulted in significant increases (p<0.0001) in weights of theindividual carcasses. Over 6 repetitions, there was an average yieldincrease of 7.14% when low scalder temperatures were used. Such yieldincrease, when applied to the plant wherein the tests were run, wouldresult in a monetary gain of approximately $38,000 per day for thatprocessor. Thus, running the scalders at lower temperatures (110 to 113on Scalder 1; 114 to 123 for Scalder 2, and 134 to 138 for Scalder 3)produces a significant increase in yield. Furthermore, no appreciablelevels of Salmonella were found in the scalder water treated with TaskerBlue®. Also, feather removal was similar for both lines.

Thus, a scalder disinfectant, such as Tasker Blue®, is an effectivemeans of reducing bacterial populations in scalder water and oncarcasses during scalding. Applying a scalder disinfectant, such asTasker Blue®, as a post-pick dip reduced cross-contamination observedduring picking. Disinfection of the scalder water and use of acid allowsscalder temperatures to be reduced significantly. And reduction ofscalder temperatures resulted in quantifiable and significant increasesin carcass yield.

Example 3

The effect of disinfectant added during scalding, spraying, and chillingon Escherichia coli counts and Salmonella prevalence was examined.

Thirty broiler chicken carcasses were collected prior to scalding in acommercial processing facility and transported to a small-scale poultryprocessing plant. Collection procedures were as described in Example 1,except as otherwise noted. These carcasses were inoculated with analadixic acid resistant strain of Salmonella typhimurium (obtained fromthe Poultry Microbiological Safety Unit at the USDA-AgriculturalResearch Service's Russell Research Center) and were allowed to attachto the carcasses for 3 hours. Fifteen control carcasses were scalded incommercial scald water, sprayed with tap water, and chilled in tap waterfor 1 hour as controls. Fifteen test carcasses were scalded incommercial scald water containing Tasker BLUE® at 2 ppm copper, sprayedwith a 2 ppm copper solution of Tasker BLUE®, and chilled in aconcentration of 2 ppm copper Tasker BLUE® for 1 hour. After treatment,carcasses were rinsed using the whole carcass rinse procedure. Half ofeach rinsate was placed on blue ice and shipped to a commercial researchlaboratory (ABC Research Corporation, Florida) for E. coli testing. Theother half was evaluated for Salmonella prevalence by direct platingonto brilliant green sulfa plates containing 200 ppm naladixic acid.Plates with characteristic bright pink colonies indicated that thecarcass was positive for Salmonella. The bacteria were removed from theplates and confirmed using serological testing.

Results showed that scalding, spraying, and chilling broiler carcasseswith Tasker BLUE® significantly decreased E. coli counts. For example,FIG. 15 shows significant Log10 reductions (p<0.05) in E. coli of 1.4,1.0, and 1.45 in Reps 1 to 3, respectively. Thus, BLUE® can lower E.coli on chicken carcasses to the USDA acceptable level of <100 cfu/mL.Results also showed that scalding, spraying, and chilling carcasses inBLUE® lowered Salmonella typhimurium prevalence on chicken carcasses(see e.g., (FIG. 16)

It is noted that reductions of this magnitude rarely, if ever, occurwhen using trisodium phosphate (TSP) or acidulated sodium chlorite(ASC). Overall, these data indicate that using BLUE® in the scalderand/or in combination with applying it using a sprayer and/or duringimmersion chilling is effective for reducing populations of E. coli andSalmonella prevalence.

Example 4

A study was conducted to determine if any of the primary ingredients inpHarlo Blue® 0020 (ammonium sulfate, sulfuric acid, copper sulfate)evolve into the air when introduced in a commercial poultry scalder. Adiagram of the process including treatment points and sampling points isdepicted in FIG. 4:1.

Air samples were collected using an impingement system as depicted inFIG. 4:2. The air was pulled, using a vacuum pump (Welch Dryfast UltraVacuum Pump), at a rate of 1.2 L/minute through 100 mL of deionizedwater for 5 minutes. The total amount of air evaluated was 6.0 L foreach sample. This was conducted over a two hour period at the Pilgrim'sPride poultry processing plant in Athens, Ga. For the controls, air wassampled above the scalder without the addition of any pHarlo Blue® 0020.A total of 10 samples were collected for the controls. The scalder wasdosed with pHarlo Blue® 0020 until a pH of 2.2 was achieved. A total of6 air samples were collected for the treated scalder water. All sampleswere collected into a glass sample jar and decanted into sterile Nalgenebottles. Immediately after collection, all samples were placed on iceand sent via overnight express to Enthalpy Analytical Laboratories forchemical analysis.

For ammonium sulfate, samples were evaluated by testing the water forthe presence of ammonia according to the procedures outlined in EPA CTM027. Analysis was performed using a Waters 430 conductivity detectorattached to a Hewlett-Packard series 1100 High Performance LiquidChromatograph. A calibration curve was analyzed prior to the samplesyielding a suitable correlation of 0.99930. Ammonia eluted atapproximately 3.0 minutes, separated well, and was easily identified.Ammonium sulfate was determined by calculation from the ammonia data.

For sulfuric acid, samples were evaluated by testing the water for thepresence of sulfate using a Waters 430 conductivity detector attached toa Hewlett-Packard series 1100 High Performance Liquid Chromatograph incombination with an Alltech ERIS 1000HP Autosuppressor. Separation wasaccomplished by a Dionex IonPac AS14A 250×4.0 mm analytical column using8.0 mM Na₂CO₃/1.0 mM NaHCO₃ as the eluent at 1.2 mL per minute. Acalibration curve was analyzed prior to the samples yielding a suitablecorrelation of 0.99922. Sulfate eluted at approximately 9.6 minutes,separated well, and was easily identified. Sulfuric acid was determinedby calculation from the sulfate data.

For copper sulfate, samples were evaluated by testing the water for thepresence of copper using a Perkin Elmer ELAN 6100 ICP-MS. Copper wasconverted to copper sulfate by multiplication of the copper data by themolecular weight of copper sulfate pentahydrate, divided by themolecular weight of copper.

All sample numbers were encoded to prevent identification duringanalysis. The data were subjected to a two-tailed t-test using theStatistic Analytical Software (SAS) program.

Results showed that the levels of the three main ingredients in pHarloBlue® 0020 (ammonium sulfate, sulfuric acid, and copper sulfate) werenot elevated in the air sampled above the scalder when the scald tankwas dosed with pHarlo Blue® 0020 (see e.g., FIG. 18). In fact, ammoniumsulfate was significantly higher in the air above the untreated scalderwater. No significant differences (p<0.05) were observed for sulfuricacid or copper sulfate levels in the air above the untreated (control)and treated scalder water. From these results, it is apparent thatdosing the scalder with pHarlo Blue® 0020 resulted in no significantincrease in the levels of any of the chemical components in the airdirectly above the scalder. Further, in multiple pilot scale studies,along with the study described herein, none of the personnel workingaround the scalder described having any adverse affects associated withbreathing the air around the scalder after dosing it with pHarlo Blue®0020. Thus, emission of any of the components of pHarlo Blue® 0020 intothe air during scalding is inconsequential.

Example 5

The inhibitory activity of acidic buffered copper-containingdisinfection agents was determined against Escherichia coli ATCC 11229.The disinfection agent was commercially available Tasker Blue® (sulfuricacid, ammonium sulfate, copper sulfate pentahydrate).

Test samples were prepared for testing at pH levels of 2.0, 2.5, 3.0,3.5, and 4.0 in combination with copper concentrations of 0 ppm, 1 ppm,2 ppm, and 3 ppm. Tryptic soy Broth was prepared half strength as astandard inoculum of 0.5 McFarland. The test sample was added to asterile tube, along with the same amount of standardized Escherichiacoli ATCC 11229 inoculum. The pH of the sample was recorded and adjustedas indicated on the test sample bottle. Tubes were incubated for 24hours at 35° C. and the inhibitory concentration was determined as thelowest concentration showing visible inhibition of the growth of theorganism. All samples were run in duplicate along with positive andnegative growth controls. Final pH of test samples were recordedfollowing completion of 24 hour incubation.

Results showed that complete inhibition of microbial growth was achievedwith all solutions except the following solutions, in which microbialgrowth was detected: pH 4.0 Cu 0 ppm; pH 4.0 Cu 1 ppm; pH 4.0 Cu 2 ppm;pH 4.0 Cu 3 ppm.

Example 6

The inhibitory activity of acidic buffered disinfection agents onaerobic plate count (APC).

Five formulations were tested.

Mark I: a 24 hour high temperature reaction process at approximately300-350° F. with a stabilization step after overnight cooling. Composedof reacting 98% sulfuric acid with a 26-28% by weight ammonium sulfatein water solution. The order of addition was ammonium sulfate solutionto sulfuric acid. Electrolysis of the reacting solution was applied for1 hour at the start of the process. The stabilization step was theaddition of more ammonium sulfate solution to ensure that the reactionis complete. The Tasker Clear product formed was a buffered acidsolution of a strong acid (sulfuric acid) and a salt (ammonium sulfate)of a strong acid and strong base.

Mark II: a 2 hour low temperature reaction process at approximately200-210° F. with a stabilization step immediately after the 1 hourelectrolysis period. This was the same process as in the Mark I productabove except that it was performed at a lower temperature and a shorterperiod of time. The ingredient amounts were adjusted to account for nolost of water as was seen in the Mark I process. The Tasker Clearproduct formed was a buffered acid solution of a strong acid (sulfuricacid) and a salt (ammonium sulfate) of a strong acid and strong base.

Mark III: a low temperature reaction process in which the 98% sulfuricacid was added slowly to a 30% by weight ammonium sulfate solution. Theaddition was done continuously until all the ammonium sulfate solutionwas added. There was no stabilization step. The addition order was thereverse of the Mark I, II, IV, and V processes. The temperature wasmaintained in the 150-200° F. range during the addition process. Noelectrolysis was performed during this process and hence the name ‘coldprocess’ was given to it. The Tasker Clear product formed was a bufferedacid solution of a strong acid (sulfuric acid) and a salt (ammoniumsulfate) of a strong acid and strong base.

Mark IV: a 4 hour high temperature reaction process at approximately300-350° F. with a stabilization step after cooling. Composed ofreacting 98% sulfuric acid with a 26-28% by weight sodium sulfate inwater solution. The order of addition was sodium sulfate solution tosulfuric acid. Electrolysis of the reacting solution was applied for 1hour at the start of the process. The stabilization step was theaddition of more sodium sulfate solution to ensure that the reaction iscomplete. The Tasker Clear product formed was a buffered acid solutionof a strong acid (sulfuric acid) and a salt (sodium sulfate) of a strongacid and strong base. (Note: In this process sodium sulfate wassubstituted for ammonium sulfate.)

Mark V: a 4 hour high temperature reaction process at approximately300-350° F. with a stabilization step after cooling. Composed ofreacting 98% sulfuric acid with a 26-28% by weight sodium sulfate inwater solution. The order of addition was sodium sulfate solution tosulfuric acid. There was no electrolysis during this process (coldprocess). The stabilization step was the addition of more sodium sulfatesolution to ensure that the reaction was complete. The Tasker Clearproduct formed was a buffered acid solution of a strong acid (sulfuricacid) and a salt (sodium sulfate) of a strong acid and strong base.(Note: In this process sodium sulfate was substituted for ammoniumsulfate, and no electrolysis was performed.)

Results showed that all formulations exponentially reduced the aerobicplate count (see e.g., Table 2).

TABLE 2 Log₁₀ Log Log₁₀ Log Time Counts cfu/ml cfu/ml Reduction TimeCounts cfu/ml cfu/ml Reduction Butterfield Buffer Control DI WaterControl 0 845 2.93 0 1015 3.01 5 780 2.89 5 1075 3.03 15 785 2.89 15 9402.97 Ave = 2.90 Ave = 3.00 Mark I Solution Mark II Solution 0 140 2.150.85 0 100 2.00 1.00 5 25 1.40 1.60 5 30 1.48 1.52 15 5 0.70 2.30 15 00.00 3.00 Mark III Solution Mark IV Solution 0 65 1.81 1.19 0 110 2.040.96 5 0 0.00 3.00 5 40 1.60 1.40 15 0 0.00 3.00 15 0 0.00 3.00 Mark VSolution 0 125 2.10 0.90 5 20 1.30 1.70 15 5 0.70 2.30 NOTES: * LogReduction based on DI Water average log₁₀ = 3.00 ** Counts are theaverage of duplicate APC plates

1. A method of reducing a microbial population on an animal carcassduring processing comprising the steps of: a) scalding an animalcarcass; b) removing feathers, hair, or hide from the scalded carcass;c) eviscerating the defeathered, dehaired, or dehided carcass; d)washing the eviscerated carcass; e) chilling the eviscerated carcass;and f) applying to the carcass during processing a disinfectioncomposition comprising an acid and a buffer, in an amount and timesufficient to reduce a microbial population; wherein applying thedisinfection composition (f) is performed during or immediately after atleast one of steps a, b, c, d, and e.
 2. The method of claim 1 furthercomprising the steps of: (g) recovering at least a portion of theapplied disinfection composition; (h) adding to the recoveredcomposition a sufficient amount of disinfection composition to yield arecycled disinfection composition; and (i) applying the recycledcomposition to a carcass during processing; wherein applying therecycled disinfection composition (i) is performed during or immediatelyafter at least one of steps a, b, c, d, and e.
 3. The method of claim 1further comprising the step of applying the disinfection composition toan animal prior to or immediately after it is sacrificed to form ananimal carcass.
 4. The method of claim 1 wherein applying thedisinfection composition comprises submersing, rinsing, or spraying thecarcass in or with the disinfection composition.
 5. The method of claim2 wherein applying the disinfection composition or the recycledcomposition comprises submersing, rinsing, or spraying the carcass in orwith the disinfection composition or the recycled composition.
 6. Themethod of claim 1 wherein applying the disinfection composition isperformed at least by (1) submersing the carcass during scalding and (2)rinsing, spraying, or submersing the carcass after scalding but beforeeviscerating.
 7. The method of claim 6 wherein rinsing, spraying, orsubmersing the carcass after scalding but before eviscerating isperformed at a sanitization station, wherein the sanitization station isintermittently fluidly connected to an apparatus for removing feathers,hair, or hide; an apparatus for scalding, or both an apparatus forremoving feathers, hair, or hide and an apparatus for scalding; so as toallow transfer of recycled composition from the sanitization station tothe feather, hair, or hide removal apparatus, the scalder apparatus, orboth the feather, hair, or hide removal apparatus and the scalderapparatus.
 8. The method of claim 1 wherein applying the disinfectioncomposition is performed at least by (1) submersing the carcass duringscalding; (2) rinsing, spraying, or submersing the carcass afterscalding and before eviscerating; and (3) submersing the carcass duringchilling.
 9. The method of claim 8 wherein rinsing, spraying, orsubmersing the carcass after scalding but before eviscerating isperformed at a sanitization station, wherein the sanitization station isintermittently fluidly connected to an apparatus for removing feathers,hair, or hide; an apparatus for scalding, or both an apparatus forremoving feathers, hair, or hide and an apparatus for scalding; so as toallow transfer of recycled composition from the sanitization station tothe feather, hair, or hide removal apparatus, the scalder apparatus, orboth the feather, hair, or hide removal apparatus and the scalderapparatus.
 10. The method of claim 1 wherein application of thedisinfection composition occurs during submersion scalding, whereinscalding occurs at a reduced temperature so as to increase post-scaldingcarcass yield.
 11. The method of claim 10 wherein scalding in at leastone scalding tank occurs at a temperature of about 110° F. to less than123° F.
 12. The method of claim 11 wherein scalding the animal carcassoccurs in at least three scalding tanks; a first scalding tank operatedat about 110° F. to about 120° F.; a second scalding tank operated atabout 110° F. to about 125° F.; and a third scalding tank operated atabout 120° F. to about 140° F.
 13. The method of claim 1 wherein thedisinfection composition is of a pH of about 1.5 to about
 4. 14. Themethod of claim 13 wherein the disinfection composition is of a pH ofabout 2 to about
 3. 15. The method of claim 1 wherein the disinfectioncomposition comprises (i) sulfuric acid and (ii) ammonium sulfate orsodium sulfate.
 16. The method of claim 1 wherein the disinfectioncomposition further comprises an antimicrobial metal.
 17. The method ofclaim 16 wherein the antimicrobial metal is selected from the groupconsisting of copper, zinc, magnesium, silver, and iron.
 18. The methodof claim 17 wherein antimicrobial metal is copper in an active ionicform.
 19. The method of claim 18 wherein the disinfection compositionhas a copper concentration of about 1 ppm to about 20 ppm or is added tocarcass processing water in an amount sufficient to provide a copperconcentration of about 1 ppm to about 20 ppm.
 20. The method of claim 19wherein the disinfection composition has a copper concentration of about2 ppm to about 4 ppm or is added to carcass processing water in anamount sufficient to provide a copper concentration of about 2 ppm toabout 4 ppm.
 21. The method of claim 20 wherein the disinfectioncomposition has a copper concentration of about 3 ppm or is added tocarcass processing water in an amount sufficient to provide a copperconcentration of about 3 ppm.
 22. The method of claim 1 wherein thedisinfection composition comprises (i) sulfuric acid, (ii) ammoniumsulfate or sodium sulfate, and (iii) copper sulfate.
 23. The method ofclaim 22 wherein the disinfection composition comprises sulfuric acid,ammonium sulfate, and copper sulfate.
 24. The method of claim 23 whereinthe disinfection composition comprises about 98% to about 99% water;about 0.1% to about 0.5% copper sulfate; about 0.1% to about 0.5%sulfuric acid; and about 0.1% to about 0.5% ammonium sulfate; and thedisinfection composition has a pH of about 2 to about 3; a specificgravity at 25° C. of about 1.002; a boiling point of about 212° F.; anda freezing point of about 32° F.
 25. The method of claim 1 wherein thedisinfection composition further comprises a stabilizing agent, wettingagent, hydrotrope, thickener, foaming agent, acidifier, pigment, dye,surfactant, or a combination thereof.
 26. The method of claim 1 whereinthe carcass comprises poultry, red meat, or pork.
 27. The method ofclaim 26 wherein the carcass is a poultry carcass.
 28. A carcassprocessing system comprising: a scalding station; a feather, hair, orhide removal station; and a sanitization station; wherein each stationis intermittently fluidly connected via a buffered acidic disinfectioncomposition.
 29. The carcass processing system of claim 28 wherein thecarcass comprises poultry, red meat, or pork.
 30. The carcass processingsystem of claim 28 wherein the disinfection composition is of a pH ofabout 1.5 to about
 4. 31. The carcass processing system of claim 28wherein the disinfection composition comprises (i) sulfuric acid, (ii)ammonium sulfate or sodium sulfate, and (iii) an antimicrobial metal.32. The carcass processing system of claim 31 wherein the antimicrobialmetal is copper in an active ionic form and the disinfection compositionhas a copper concentration of about 1 ppm to about 20 ppm or is added tocarcass processing water in an amount sufficient to provide a copperconcentration of about 1 ppm to about 20 ppm.
 33. The carcass processingsystem of claim 28 comprising at least three scalding tanks, wherein afirst scalding tank is operated at about 110° F. to about 120° F.; asecond scalding tank is operated at about 110° F. to about 125° F.; anda third scalding tank is operated at about 120° F. to about 140° F.